[PATCH v3 6/7] tpm: expose spaces via a device link /dev/tpmrm

[Jarkko Sakkinen]

From: James Bottomley 

Currently the tpm spaces are not exposed to userspace.  Make this
exposure via a separate device, which can now be opened multiple times
because each read/write transaction goes separately via the space.

Concurrency is protected by the chip->tpm_mutex for each read/write
transaction separately.  The TPM is cleared of all transient objects
by the time the mutex is dropped, so there should be no interference
between the kernel and userspace.

Signed-off-by: James Bottomley 
Tested-by: Jarkko Sakkinen 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen 
---
 drivers/char/tpm/Makefile|  3 +-
 drivers/char/tpm/tpm-chip.c  | 58 ++-
 drivers/char/tpm/tpm-interface.c | 13 ++--
 drivers/char/tpm/tpm.h   |  4 +++
 drivers/char/tpm/tpmrm-dev.c | 65 
 5 files changed, 139 insertions(+), 4 deletions(-)
 create mode 100644 drivers/char/tpm/tpmrm-dev.c

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 10e5827..23681f0 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -3,7 +3,8 @@
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
 tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
-tpm-dev-common.o tpm1_eventlog.o tpm2_eventlog.o tpm2-space.o
+tpm-dev-common.o tpmrm-dev.o tpm1_eventlog.o tpm2_eventlog.o \
+ tpm2-space.o
 tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
 tpm-$(CONFIG_OF) += tpm_of.o
 obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 364d92e..3db38f9 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -33,6 +33,7 @@ DEFINE_IDR(dev_nums_idr);
 static DEFINE_MUTEX(idr_lock);
 
 struct class *tpm_class;
+struct class *tpmrm_class;
 dev_t tpm_devt;
 
 /**
@@ -132,6 +133,14 @@ static void tpm_dev_release(struct device *dev)
kfree(chip);
 }
 
+static void tpm_devs_release(struct device *dev)
+{
+   struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
+
+   /* release the master device reference */
+   put_device(>dev);
+}
+
 /**
  * tpm_chip_alloc() - allocate a new struct tpm_chip instance
  * @pdev: device to which the chip is associated
@@ -168,27 +177,47 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->dev_num = rc;
 
device_initialize(>dev);
+   device_initialize(>devs);
 
chip->dev.class = tpm_class;
chip->dev.release = tpm_dev_release;
chip->dev.parent = pdev;
chip->dev.groups = chip->groups;
 
+   chip->devs.parent = pdev;
+   chip->devs.class = tpmrm_class;
+   chip->devs.release = tpm_devs_release;
+   /* get extra reference on main device to hold on
+* behalf of devs.  This holds the chip structure
+* while cdevs is in use.  The corresponding put
+* is in the tpm_devs_release
+*/
+   get_device(>dev);
+
if (chip->dev_num == 0)
chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
else
chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
 
+   chip->devs.devt =
+   MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
+
rc = dev_set_name(>dev, "tpm%d", chip->dev_num);
if (rc)
goto out;
+   rc = dev_set_name(>devs, "tpmrm%d", chip->dev_num);
+   if (rc)
+   goto out;
 
if (!pdev)
chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
 
cdev_init(>cdev, _fops);
+   cdev_init(>cdevs, _fops);
chip->cdev.owner = THIS_MODULE;
+   chip->cdevs.owner = THIS_MODULE;
chip->cdev.kobj.parent = >dev.kobj;
+   chip->cdevs.kobj.parent = >devs.kobj;
 
chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!chip->work_space.context_buf) {
@@ -199,6 +228,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
return chip;
 
 out:
+   put_device(>devs);
put_device(>dev);
return ERR_PTR(rc);
 }
@@ -263,7 +293,6 @@ static int tpm_add_char_device(struct tpm_chip *chip)
"unable to cdev_add() %s, major %d, minor %d, err=%d\n",
dev_name(>dev), MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
-
return rc;
}
 
@@ -277,6 +306,29 @@ static int tpm_add_char_device(struct tpm_chip *chip)
return rc;
}
 
+   if (chip->flags & TPM_CHIP_FLAG_TPM2)
+   rc = cdev_add(>cdevs, chip->devs.devt, 1);
+   if (rc) {
+   dev_err(>dev,
+   "unable to cdev_add() %s, major %d, minor %d, err=%d\n",
+   dev_name(>devs), 

[PATCH v3 6/7] tpm: expose spaces via a device link /dev/tpmrm

[Jarkko Sakkinen]

From: James Bottomley 

Currently the tpm spaces are not exposed to userspace.  Make this
exposure via a separate device, which can now be opened multiple times
because each read/write transaction goes separately via the space.

Concurrency is protected by the chip->tpm_mutex for each read/write
transaction separately.  The TPM is cleared of all transient objects
by the time the mutex is dropped, so there should be no interference
between the kernel and userspace.

Signed-off-by: James Bottomley 
Tested-by: Jarkko Sakkinen 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen 
---
 drivers/char/tpm/Makefile|  3 +-
 drivers/char/tpm/tpm-chip.c  | 58 ++-
 drivers/char/tpm/tpm-interface.c | 13 ++--
 drivers/char/tpm/tpm.h   |  4 +++
 drivers/char/tpm/tpmrm-dev.c | 65 
 5 files changed, 139 insertions(+), 4 deletions(-)
 create mode 100644 drivers/char/tpm/tpmrm-dev.c

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 10e5827..23681f0 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -3,7 +3,8 @@
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
 tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
-tpm-dev-common.o tpm1_eventlog.o tpm2_eventlog.o tpm2-space.o
+tpm-dev-common.o tpmrm-dev.o tpm1_eventlog.o tpm2_eventlog.o \
+ tpm2-space.o
 tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
 tpm-$(CONFIG_OF) += tpm_of.o
 obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 364d92e..3db38f9 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -33,6 +33,7 @@ DEFINE_IDR(dev_nums_idr);
 static DEFINE_MUTEX(idr_lock);
 
 struct class *tpm_class;
+struct class *tpmrm_class;
 dev_t tpm_devt;
 
 /**
@@ -132,6 +133,14 @@ static void tpm_dev_release(struct device *dev)
kfree(chip);
 }
 
+static void tpm_devs_release(struct device *dev)
+{
+   struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
+
+   /* release the master device reference */
+   put_device(>dev);
+}
+
 /**
  * tpm_chip_alloc() - allocate a new struct tpm_chip instance
  * @pdev: device to which the chip is associated
@@ -168,27 +177,47 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->dev_num = rc;
 
device_initialize(>dev);
+   device_initialize(>devs);
 
chip->dev.class = tpm_class;
chip->dev.release = tpm_dev_release;
chip->dev.parent = pdev;
chip->dev.groups = chip->groups;
 
+   chip->devs.parent = pdev;
+   chip->devs.class = tpmrm_class;
+   chip->devs.release = tpm_devs_release;
+   /* get extra reference on main device to hold on
+* behalf of devs.  This holds the chip structure
+* while cdevs is in use.  The corresponding put
+* is in the tpm_devs_release
+*/
+   get_device(>dev);
+
if (chip->dev_num == 0)
chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
else
chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
 
+   chip->devs.devt =
+   MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
+
rc = dev_set_name(>dev, "tpm%d", chip->dev_num);
if (rc)
goto out;
+   rc = dev_set_name(>devs, "tpmrm%d", chip->dev_num);
+   if (rc)
+   goto out;
 
if (!pdev)
chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
 
cdev_init(>cdev, _fops);
+   cdev_init(>cdevs, _fops);
chip->cdev.owner = THIS_MODULE;
+   chip->cdevs.owner = THIS_MODULE;
chip->cdev.kobj.parent = >dev.kobj;
+   chip->cdevs.kobj.parent = >devs.kobj;
 
chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!chip->work_space.context_buf) {
@@ -199,6 +228,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
return chip;
 
 out:
+   put_device(>devs);
put_device(>dev);
return ERR_PTR(rc);
 }
@@ -263,7 +293,6 @@ static int tpm_add_char_device(struct tpm_chip *chip)
"unable to cdev_add() %s, major %d, minor %d, err=%d\n",
dev_name(>dev), MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
-
return rc;
}
 
@@ -277,6 +306,29 @@ static int tpm_add_char_device(struct tpm_chip *chip)
return rc;
}
 
+   if (chip->flags & TPM_CHIP_FLAG_TPM2)
+   rc = cdev_add(>cdevs, chip->devs.devt, 1);
+   if (rc) {
+   dev_err(>dev,
+   "unable to cdev_add() %s, major %d, minor %d, err=%d\n",
+   dev_name(>devs), MAJOR(chip->devs.devt),
+   MINOR(chip->devs.devt), rc);
+   tpm_del_char_device(chip, true);
+   return rc;
+   }
+
+   if (chip->flags